Panoramic Image Tone Correction Using Ghost Information
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Solution Overview
Problem
When generating panoramic images by blending multiple images taken under different conditions, such as varying exposure values and lens shadings, existing methods often result in artifacts at the seam connecting the images, leading to unnatural tone differences and afterimages.
Innovation Solution
An apparatus and method that acquire ghost information from overlapping regions of images using a cost map and optimal threshold, generate a tone correction map through global and local tone correction functions, and apply bidirectional weighting to correct the images, ensuring accurate and natural tone alignment between the left and right images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tone correction is performed after blending multiple images, then the blending process is simple, but artifacts occur at the seam connecting the images
Solution Approach 1:
The patent applies preliminary action by performing tone correction on each individual image before the blending process. The tone correction unit adjusts the tone of each image based on its specific characteristics (exposure value, lens shading, gradation) prior to merging, ensuring that when the images are blended, the tones are already aligned and matched, preventing seam artifacts from occurring in the final panorama.
2Manufacturing precision
If each image is corrected individually before blending, then tone alignment is improved, but the processing time increases
Solution Approach 1:
The patent merges multiple tone correction operations into a unified process. Instead of correcting each image completely independently with separate full processing chains, the system uses a coordinated approach where the tone correction unit processes multiple images simultaneously, sharing computational resources and processing logic. This combined processing reduces the total time required compared to sequential independent corrections while maintaining accurate tone alignment.
3Productivity
If ghost information is ignored in overlapping regions, then the processing is faster, but afterimages occur due to tone differences
Solution Approach 1:
The patent converts the harmful ghost information (misaligned pixel data in overlapping regions) into a beneficial correction signal. The tone correction unit specifically analyzes the overlapping regions to identify ghost information and uses this information to calculate appropriate tone correction values. By turning the problematic ghost data into a diagnostic tool, the system achieves more accurate tone matching in overlapping areas, eliminating afterimage artifacts while maintaining processing efficiency.
Data Source
AI summary
Apparatus and method for correcting a tone of a panoramic image. An image processing apparatus may acquire, from an overlapping region of a left image and a right image, ghost information based on an optimal threshold and a cost map in which a similarity between the left image and the right image is reflected, may generate a tone correction map based on a global tone correction function generated using the ghost information in the overlapping region, and based on a local tone correction level generated using local information of an optimal seam, and may correct the left image and the right image using a final tone correction map generated by applying, to the tone correction map, a weighting based on the left image and a weighting based on the right image.